<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			/*
			 根据用户的输入数，
			 1.输出对应的月份 1一月 2二月 3三月 4四月...12十二月
			 2.输出对应的天数  31    29   31    30
			 
			*/
			var month = prompt("请输入月份对应的数");
			// console.log(typeof month);
			month = month - 0; //隐式转换
			// console.log(typeof month);
			switch (month) {
				case 1:
				case 3:
				case 5:
				case 7:
				case 8:
				case 10:
				case 12:
					console.log("31");
					break;
				case 2:
					console.log("29");
					break;
				case 4:
				case 6:
				case 9:
				case 11:
					console.log("30");
					break;
				default:
					console.log("无");
			}
		</script>
	</head>
	<body>
	</body>
</html>
